Underneath London, there's a temporary city waiting to be discovered... One inspired by Metropolis and graffitti artist Banksy, and created by Kevin Spacey and friends. Strange and true, Tunnel 228 is alternate reality come true.

Tunnel is actually a performance art installation housed in a network of unused Victorian railway tunnels under the UK's capital city, populated by the work of a number of artists brought together by art group Punchdrunk and Spacey (in his capacity as artistic director of the Old Vic theater). The limited-run creation is so popular that it's to be repeated later this year, allowing more people to experience a London that never was, right under their feet.